Olefin metathesis is a catalytic process including, as a key step, a reaction between a first olefin and a first transition metal alkylidene complex, thus producing an unstable intermediate metallacyclobutane ring which then undergoes transformation into a second olefin and a second transition metal alkylidene complex according to equation (1) hereunder. Reactions of this kind are reversible and in competition with one another, so the overall result heavily depends on their respective rates and, when formation of volatile or insoluble products occur, displacement of equilibrium.

Several exemplary but non-limiting types of metathesis reactions for mono-olefins or di-olefins are shown in equations (2) to (5) herein-after. Removal of a product, such as ethylene in equation (2), from the system can dramatically alter the course and/or rate of a desired metathesis reaction, since ethylene reacts with an alkylidene complex in order to form a methylene (M═CH2) complex, which is the most reactive and also the least stable of the alkylidene complexes.
Of potentially greater interest than homo-coupling (equation 2) is cross-coupling between two different terminal olefins. Coupling reactions involving dienes lead to linear and cyclic dimers, oligomers, and, ultimately, linear or cyclic polymers (equation 3). In general, the latter reaction called acyclic diene metathesis (hereinafter referred to as ADMET) is favoured in highly concentrated solutions or in bulk, while cyclisation is favoured at low concentrations. When intra-molecular coupling of a diene occurs so as to produce a cyclic alkene, the process is called ring-closing metathesis (hereinafter referred to as RCM) (equation 4). Cyclic olefins can be opened and oligomerised or polymerised (ring opening metathesis polymerisation (hereinafter referred to as ROMP) shown in equation 5). When the alkylidene catalyst reacts more rapidly with the cyclic olefin (e.g. a norbomene or a cyclobutene) than with a carbon-carbon double bond in the growing polymer chain, then a “living ring opening metathesis polymerisation” may result, i.e. there is little termination during or after the polymerization reaction.
A large number of catalyst systems comprising well-defined single component metal carbene complexes have been prepared and utilized in olefin metathesis. One major development in olefin metathesis was the discovery of the ruthenium and osmium carbene complexes by Grubbs and co-workers. U.S. Pat. No. 5,977,393 discloses Schiff base derivatives of such compounds, which are useful as olefin metathesis catalysts, wherein the metal is coordinated by a neutral electron donor, such as a triarylphosphine or a tri(cyclo)alkylphosphine, and by an anionic ligand. Such catalysts show an improved thermal stability while maintaining metathesis activity even in polar protic solvents. They are also able to cyclise diallylamine hydrochloride to dihydropyrrole hydrochloride. Remaining problems to be solved with the carbene complexes of Grubbs are (i) improving both catalyst stability (i.e. slowing down decomposition) and metathesis activity at the same time and (ii) broadening the range of organic products achievable by using such catalysts, e.g. providing ability to ring-close highly substituted dienes into tri- and tetra-substituted olefins.
On the other hand, living polymerisation systems were reported for anionic and cationic polymerisation, however their industrial application has been limited by the need for high-purity monomers and solvents, reactive initiators and anhydrous conditions. In contrast, free-radical polymerisation is the most popular commercial process to yield high molecular weight polymers. A large variety of monomers can be polymerised and copolymerised radically under relatively simple experimental conditions which require the absence of oxygen but can be carried out in the presence of water. However free-radical polymerisation processes often yield polymers with ill-controlled molecular weights and high polydispersities. Combining the advantages of living polymerisation and radical polymerisation is therefore of great interest and was achieved by the atom (or group) transfer radical polymerisation process (hereinafter referred as ATRP) of U.S. Pat. No. 5,763,548 involving (1) the atom or group transfer pathway and (2) a radical intermediate. This type of living polymerization, wherein chain breaking reactions such as transfer and termination are substantially absent, enables control of various parameters of the macromolecular structure such as molecular weight, molecular weight distribution and terminal functionalities. It also allows the preparation of various copolymers, including block and star copolymers. Living/controlled radical polymerization requires a low stationary concentration of radicals in equilibrium with various dormant species. It makes use of novel initiation systems based on the reversible formation of growing radicals in a redox reaction between various transition metal compounds and initiators such as alkyl halides, aralkyl halides or haloalkyl esters. ATRP is based on a dynamic equilibrium between the propagating radicals and the dormant species which is established through the reversible transition metal-catalysed cleavage of the covalent carbon-halogen bond in the dormant species. Polymerisation systems utilising this concept have been developed for instance with complexes of copper, ruthenium, nickel, palladium, rhodium and iron in order to establish the required equilibrium.
Due to the development of ATRP, further interest appeared recently for the Kharash reaction, consisting in the addition of a polyhalogenated alkane across an olefin through a radical mechanism (first published by Kharash et al. in Science (1945) 102:169) according to the following scheme (wherein X may be hydrogen or
chloro or bromo, and R and R′ may be each independently selected from hydrogen, C1-7 alkyl, phenyl and carboxylic acid or ester):
Because ATRP is quite similar to the Kharasch reaction, the latter may also be called Atom Transfer Radical Addition (hereinafter referred as ATRA) and attracted interest in transition metal catalysis. Research in this field also focused on the use of new olefins and telogens and a wide range of internal, terminal and cyclic olefins and diolefins were tested with a wide range of polyhalides including fluoro, chloro, bromo and iodo as halogen atoms, as described for instance in Eur. Polym. J. (1980) 16:821 and Tetrahedron (1972) 28:29.
Experiments have shown that the efficiency of ruthenium alkylidene complexes in olefin metathesis reactions is inversely proportional to their activity in ATRP and ATRA, i.e. the most efficient catalysts for olefin metathesis reactions display the lowest activity in ATRP and ATRA. Therefore, there is a need in the art for a catalyst component which is able to display a high efficiency both in olefin metathesis reactions and in ATRP and ATRA. There is also a need in the art for a catalyst component which is able to initiate olefin metathesis reactions under very mild conditions, e.g. at room temperature. Finally there is also a need in the art for a catalyst component which is able to initiate vinylation reactions with high efficiency.
Furthermore, since presently available synthetic routes to the catalysts of U.S. Pat. No. 5,977,393 proceed through the transformation of a ruthenium bisphosphane carbene, the development of catalysts with equivalent or better performance characteristics but synthesised directly from less expensive and readily available starting materials, including from other transition metals, still corresponds to a need in the art.
Poly-α-olefins such as polyethylene, polypropylene and copolymers of ethylene with propylene and/or but-1-ene are very widely used in various fields such as extruded, co-extruded and moulded products of all kinds. The demand for poly-α-olefins with various physical properties is continuously expanding. Therefore, in order to improve their manufacturing productivity, the increase of polyolefin yield per catalyst amount and the maintenance of catalytic activity over time during continuous production remain important issues. WO 02/02649 discloses an olefin polymerisation catalytic system comprising (A) a transition metal compound, preferably wherein the transition metal is titanium, zirconium or hafnium, having a bidentate ligand including an imine structure moiety, (B-1) a compound having a reduction ability which reacts with compound (A) to convert said imine structure moiety into a metal amine structure, and (B-2) a compound which reacts with compound (A) to form an ion pair. However, WO 02/02649 does not teach a transition metal compound wherein the metal is coordinated with a carbene ligand. Therefore there is still a need in the art for improving the olefin polymerisation catalytic activity, and maintenance thereof over time, with respect to the teaching of WO 02/02649.
The Friedlaender reaction consists of quinoline synthesis through oxidative cyclisation of 2-aminobenzyl alcohol with ketones. Exemplary ketones which may be cyclised into quinolines include acetophenone, 3-methylacetophenone, cyclohexanone, 4-phenylcyclohexanone and propiophenone and other ketones such as disclosed by Cho et al. in Chem. Commun. (2001) 2576-2577. There is a need in the art for developing new catalysts providing higher yields, under equivalent reaction conditions, in the Friedlaender reaction.
All the above needs constitute the various goals to be achieved by the present invention.